- #1
blaziken's_charizard
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1. The speed of a body of mass, m, moving horizontally, increases from u to v over a distance, d, under the influence of a constant resultant force, F, in the direction of motion. The energy transferred to the body is:
1. Fd
2. m/2*(v^2 - u^2)
3. 1/2*(mv)^2
The options are: 1 only, 2 only, 1 & 2 only or 1 & 3 only.
I'd say 1 & 3 only seeing as I recognize they are equations dealing with energy and I don't know of the equation in 2.2. A steel balling is falling with constant velocity through oil. The gravitational force acting on the ball is:
a) zero
b) reduced by the upward forces
c) less than it would be in air
d) exactly equal to the sum of the upward forces
I chose D because the other don't make sense to my knowledge.3.
The figure above shows a lamina of uniform thickness. Its centre of gravity is most likely to be at:
a) P
b) Q
c) R
d) S
Dunno why also... Q just seems right.4. In which of the following situations is the strong force associated with the contraction of a previously heated object made use of?
1) Joining sections of a railway line
2) Fitting metal rims onto wheels
3) Rivets
4) Clinical Thermometer
I'd say 1, 2, 3 and 4. Though I'm a bit skeptical about 4.5. There are four containers: A B C & D. They contain water of masses m, 2m, 3m and 4m at temperatures 20 °C, 40 °C, 60 °C and 80 °C respectively.
Which of the above must lose the most energy to cool down to 10 °C? I'd say D because it has the highest mass and would undergo the greatest temp. change and hence the value of E would be high from the equation: E=mc(t2-t1)
In which of the cases above is the average kinetic energy of the molecules the greatest?
I again say D.6. Which of the following would cause the hot air above a fire to rise?
1. Increase in speed of the air molecules
2. Expansion of the air
3. Decrease in the density of the air
I'd say all three because increase in speed = expansion = lower density = rise
7. Which of the following components may be found in both d.c. motors and a.c. generators?
1) soft iron armature
2) brushes
3) slip rings
I say 2 only
I hope I am correct. If I am not please feel free to correct me. Thank you guys :)
1. Fd
2. m/2*(v^2 - u^2)
3. 1/2*(mv)^2
The options are: 1 only, 2 only, 1 & 2 only or 1 & 3 only.
I'd say 1 & 3 only seeing as I recognize they are equations dealing with energy and I don't know of the equation in 2.2. A steel balling is falling with constant velocity through oil. The gravitational force acting on the ball is:
a) zero
b) reduced by the upward forces
c) less than it would be in air
d) exactly equal to the sum of the upward forces
I chose D because the other don't make sense to my knowledge.3.
The figure above shows a lamina of uniform thickness. Its centre of gravity is most likely to be at:
a) P
b) Q
c) R
d) S
Dunno why also... Q just seems right.4. In which of the following situations is the strong force associated with the contraction of a previously heated object made use of?
1) Joining sections of a railway line
2) Fitting metal rims onto wheels
3) Rivets
4) Clinical Thermometer
I'd say 1, 2, 3 and 4. Though I'm a bit skeptical about 4.5. There are four containers: A B C & D. They contain water of masses m, 2m, 3m and 4m at temperatures 20 °C, 40 °C, 60 °C and 80 °C respectively.
Which of the above must lose the most energy to cool down to 10 °C? I'd say D because it has the highest mass and would undergo the greatest temp. change and hence the value of E would be high from the equation: E=mc(t2-t1)
In which of the cases above is the average kinetic energy of the molecules the greatest?
I again say D.6. Which of the following would cause the hot air above a fire to rise?
1. Increase in speed of the air molecules
2. Expansion of the air
3. Decrease in the density of the air
I'd say all three because increase in speed = expansion = lower density = rise
7. Which of the following components may be found in both d.c. motors and a.c. generators?
1) soft iron armature
2) brushes
3) slip rings
I say 2 only
I hope I am correct. If I am not please feel free to correct me. Thank you guys :)